Enantioselective, NHC‐Catalyzed Annulations of Trisubstituted Enals and Cyclic N ‐Sulfonylimines via α,β‐Unsaturated Acyl Azoliums

All aboard please! A new reaction of enals and cyclic sulfonylimines, as the nucleophiles(!), is the first highly enantioselective NHC‐catalyzed annulation of trisubstituted enals. The catalytically generated α,β‐unsaturated acyl azolium undergoes a reaction with the enamine tautomer of the imine via an aza‐Claisen rearrangement as the key CC bond‐forming step. High yields and enantioselectivities were achieved using β ‐ , α,β‐, and β,β′‐substituted enals.